Mich. Comp. Laws § 38.2605
All proceedings pending and all rights and liabilities existing, acquired, or incurred under the former judges retirement system or former probate judges retirement system at the time this act takes effect are saved. Those proceedings shall be consummated pursuant to the law in effect when the proceedings were commenced. Those rights and liabilities shall be preserved pursuant to the law in effect on the day immediately preceding the effective date of this act. To the extent that either the kinds of benefits available under the former judges retirement system or former probate judges retirement system as in effect on the day immediately before the effective date of this act or the manner of calculating those benefits under the former judges retirement system or former probate judges retirement system results in a greater benefit of any kind than would otherwise be available under this act or include a benefit not otherwise available under this act, the determinations of those kinds of benefits available and the manner of calculating those benefits shall be made pursuant to the former judges retirement system or former probate judges retirement system for those members who participated in the retirement system as set forth in the former judges retirement system or former probate judges retirement system before the effective date of this act.
MCL 38.2605